Substituted 6-phenyl benzo-naphthyridines

ABSTRACT

The invention concerns new 4a,10b-cis-substituted benzonaphthyridines of the formula:   WHEREIN R1 is hydrogen, alkyl, alkoxy, alkylthio, fluorine, chlorine, bromine, nitro, trifluoromethyl, amino or acylamino, R2 is hydrogen, chlorine, alkyl or alkoxy, and R3 and R4 are both hydrogen or both methoxy, or R3 and R4 together are methylenedioxy. A process for the production thereof and intermediates therefor are also described. The compounds inhibit blood platelet aggregation.

United States Patent [1 1 Ott et al.

[451 Aug. 12, 1975 SUBSTITUTED 6-PHENYL BENZO-NAPHTHYRIDINES [75] Inventors: Hans Ott, Pfeffingen; Rudolf Suess,

Bettingen, both of Switzerland [73] Assignee: Sandoz Ltd., Basle, Switzerland [22] Filed: Oct. 19, 1973 [21] Appl. No.1 408,053

Related US. Application Data [63] Continuation-impart of Ser. No. 305,289, Nov. 10, 1972, abandoned, which is a continuation-in-part of Ser. No 303,069, Nov. 2, 1972, abandoned, which is a continuation of Ser. No. 140,239, May 4, 1971,

[52] US. Cl. 260/287 R; 260/283 S; 260/283.54; 260/286 R; 260/288 R; 260/293.85;

260/475 SC; 260/476 R; 260/240 D; 424/258 [51] Int. Cl C07d 35/10 [58] Field of Search 260/287 R, 288 R, 283 S [56] References Cited OTHER PUBLICATIONS Ott, Chemical Abstracts, Abst. German 2,123,328, 2-12-71, Vol. 76, pg., 381, No. 72495 Primary Examiner Donald G. Daus Assistant ExaminerDavid E. Wheeler Attorney, Agent, or F irm--Gerald D. Sharkin; Robert S. Honor; Thomas O. McGovern [5 7 ABSTRACT The invention concerns new 4a,l0b-cis-substituted benzo-naphthyridines of the formula:

wherein R 1 is hydrogen, alkyl, alkoxy, alkylthio, fluorine, chlorine, bromine, nitro, trifluoromethyl, amino or acylamino,

R is hydrogen, chlorine, alkyl or alkoxy, and

R and R are both hydrogen or both methoxy, or

R and R together are methylenedioxy.

A process for the production thereof and intermediates therefor are also described.

The compounds inhibit blood platelet aggregation.

70 Claims, No Drawings SUBSTITUTED 6-PHENYL BENZO-NAPHTHYRIDINES This application is a continuation-in-part of US. Pat. application Ser. No. 305,289, filed Nov. 10, 1972, now abandoned, which in turn is a continuation in part of US. Pat. application Ser. No. 303,069, filed Nov. 2, 1972, now abandoned, which in turn is a continuation in part of US, Pat. application Ser. No. 140,239, filed May 4, 1971, now abandoned.

The invention concerns novel benzo-naphthyridine derivatives.

In accordance with the invention, there is provided new 4a,10b-cis-substituted benzo-naphthyridines of formula I,

wherein R, is hydrogen, alkyl of one to three carbon atoms, alkoxy of one to three carbon atoms or al kylthio of one to three carbon atoms, fluorine, bromine, chlorine, nitro, trifluoromethyl, amino or acylamino, wherein the acyl group is selected from; aliphatic acyl of one to 18 carbon atoms, benzoyl, benzoyl wherein the benzene ring is substituted by radicals X and Y, X being lower alkyl of one to four carbon atoms, lower alkoxy of one to four carbon atoms, fluorine, chlorine or bromine, and Y being hydrogen, lower alkyl of one to four carbon atoms, lower alkoxy of one to four carbon atoms, or chlorine, phenyl-alkenoyl, wherein the alkylene section has one to three carbon atoms, cinnamoyl, phenylalkenoyl as defined above or cinnamoyl which are substituted in the benzene ring by radicals X and Y which are as defined above, or the radical ACO-, A being a or 6-membered heterocyclic aromatic ring containing an oxygen, nitrogen or sulfur atom,

R is hydrogen, chlorine, alkyl of one to three carbon atoms or alkoxy of one to three carbon atoms, and

R and R. are both hydrogen or both methoxy, or

R and R together are methylenedioxy, and pharmaceutically acceptable acid addition salts thereof.

It will be appreciated that the acyl moiety of acylamino may be regarded as CO-R.

When the radical R is alkyl of up to l7 carbon atoms, this may, for example, signify butyl, tertbutyl, pentyl, octyl, undeeyl or heptadecyl. This radical preferably contains four to eight carbon atoms.

When R is a 5- or 6-membered heteroaromatic ring containing a hetero atom of the series oxygen, nitrogen or sulphur, and bound to the carbonyl group with a carbon atom, this especially signifies furyl, thienyl or pyridyl, preferably 2-furyl, 2-thienyl or 3-pyridyl.

Alkylene in phenylalkylene especially contains one or two carbon atoms and preferably signifies methylene.

When the radicals X and/or Y are alkyl or alkoxy of one to four carbon atoms, these radicals especially contain one or two carbon atoms and preferably signify methyl or methoxy.

When R is an aromatic group, this preferably signifies phenyl, styryl or benzyl substituted by X and Y, wherein X is hydrogen, methyl, methoxy, fluorine, chlorine or bromine, and Y is hydrogen, methyl or methoxy.

The radical R-CONH-- is preferably in the 4 position of the phenyl radical to which it is bound.

A class is provided of compounds of formula,

CH O

l NHCOR' wherein R R and R, are as defined above, and R, is hydrogen, alkyl of one to three carbon atoms, alkoxy of one to three carbon atoms or alkylthio of one to three carbon atoms, fluorine, chlorine. bro mine, nitro or trifluoromethyl, to obtain a compound of formula la,

wherein R R R and Rg are as defined above, b. reducing a compound of formula lb,

r I R 3 J wherein R R and R are; as defined above, to obtain a compound of formula Ic,

wherein R R and R are as defined above, or c. acylating a compound of formula lc to obtain a compound of formula Id,

wherein R R and .R and acyl are as defined above.

The resulting compound of formula I may be isolated in the form of a free base or as an acid addition salt thereof. The cyclization of process variant (u) is a Bischler- Napieralski reactionand is suitably effected by heating an'amide of formula II with an excess of phosphorus oxychloride for some time, e.g. for l to l0 hours, at a temperature from C to the boiling temperature of the reaction mixture. The ring closure may also be effected using phosphorus oxychloride or phosphorus pentoxide in the presence of an inert solvent, e.g. a chlorinated hydrocarbon such as chloroform, or in a cyclic hydrocarbon such as benzene, toluene, xylene or tetraline, at an elevated temperature, preferably at the boiling temperature of the reaction mixture.

Other reagents which are especially suitable for the cyclization are polyphosphoric acid or phosphorus pentachloride.

The cyclization does not change the steric arrangement of the substituents on the piperidine ring, so that the stereochemistry in positions 4a and 10b (ring linkage) of the resulting l,2,3,4,4a,lObhexahydro-benzo[c][ 1,6]naphthyridine derivatives of formula I agrees with that of the starting materials.

The reduction of the nitro group in the compounds of formula lb in process variant (b) may, for example, be effected with iron tumings and an acid such as dilute hydrochloric acid. If desired an inert solvent, e. g. a lower alcohol such as ethanol, may be used. The reaction is suitably carried out at an elevated temperature, e.g. at the boiling temperature of the reaction mixture.

Process variant (0) is effected in conventional manner by treating the amino derivatives of formula Ic with an acylating agent, e.g. formic acid or a carboxylic acid chloride or anhydride, optionally in an inert solvent and at an elevated temperature.

The compounds of formula I may be isolated and purified in accordance with known methods.

The compounds of formula II may, for example, be obtained by reacting a compound of formula III,

III

wherein R and R are as defined above,

and which is cis-substituted in the 3,4-position,

60 with a compound of formula IV,

, .3UcH -cooa R i y wherein R and R are as defined above, V is converted into an alkyl (one to four carbon atoms) ester thereof. e.g. with an excess of the corresponding alkanol in the presence of an acid, e.g. hydrochloric acid. The resulting ester is reacted in the presence of a strongly basic condensation agent, such assodium ethylate-in toluene, with a dialkyl (alkyl of l to 4 carbon atomslester of oxalic acid, The resulting compound, of formula VI,

}U CH-COOR CO VI Bl; IOOR' o 6 wherein R and R are as defined above, and each of R and R is alkyl of one to four carbon atoms, d o is treated with formaldehyde, e.g. with aqueous formalin, in the presence of an alkali such as potassium carbonate, and the reaction product is distilled, whereby a phenylacrylic acid ester of formula VI I,Z

, CH R 2 1 y u A gr inc-c003 4 7 wherein R R andR are as defined above,.

is obtained. a it a The phenylacrylic acid ester of formula VII is condensed with methyl-amine and the condensation product is reacted with a compound of formula VIII,

wherein Y is chlorine or bromine, and I R is alkyl of one to four carbon atoms, 1

in the presence or an acid-binding agent,;whereby. a

compound of formula IX,

3 (in H l 2 RQUCOORG 000R wherein R R R and R are as defined above, is obtained fllowever, a compound of formula IX may also be obtained by reacting a phenylacrylic acid ester of formula VII with an amino acid esterof formula X,

wherein R is as defined above. The compound of formula IX is cyclized by heating with a strongly basiccondensation agent, e.g. sodium hydride in toluene, and the resulting product is converted into the corresponding piperidone of formula XI, i

wherein R and R are as defined above, by hydrolysis and decarboxylation, e. g. by heating in an aqueous mineral acid such as 3-6 N hydrochloric acid.

The piperidones of formula XIare reacted with hydroxylamine hydrochloride and the resulting oximes are reduced to the correspondingpiperidyl amines, e.g. by hydrogenation over a metal catalyst such as Raney nickel, by reaction with-complex alkali metal hydrides such as lithium aluminum hydride, or with metallic sodium in a lower alkanol. The piperidones of formula XI may also be hydrogenated catalytically in the presence of ammonia, e.g. in a solution of ammonia in ethanol in the presence of Raney nickel at an elevated temperature and under pressure, whereby the -.imines resulting as intermediaries are reduced in situ to the corresponding piperidylamines. The reductions mentioned above generally" yield mixtures of the cisand transracemates, the percentage composition of which will vary depending on the reaction conditions. The cispiperidylamines of formula III may be separated from these mixtures as racemates inaccordance with known methods, e.g. by fractional crystallization of their acid addition salts or by adsorption chromatography. Insofar as the production of the starting materials is not described, these are known or may be produced in accordance with known processes or in a manner analogous to the processes described herein or to known processes. v t

The, compounds of formula I and their pharmacologically tolerable acid addition salts are useful because they possess pharmacological activity in animals. More particularly, the compounds are useful in the treatment of thrombosis as indicated by their properties in inhibiting blood plateletaggregation, this property being illustrated by the inhibition of such aggregation caused in vitro by adenosine diphosphate in blood platelet-rich rabbit plasma (turbidimetric method in accordance with Born), and by inhibition of thrombosis in the aortic loop rat preparation. Inhibition commences at concentrations from about l #g/ml to about 30 tg/ml in the in vitro test.

For the above-mentioned use, the dose will naturally vary depending on the compound employed, the mode of administration and the treatment desired. However, satisfactory results are obtained in warm-blooded animals at a dose of from about 0.1 to about mg/kg animal body weight, conveniently given in divided doses two to three times a day, or in sustained release form. For the larger mammals, the daily dosage is from about 10 mg to about 400 mg, and dosage forms suitable for oral administration contain from about 3 to about 200 mg of the compound admixed with the solid or liquid pharmaceutical carrier or diluent.

The compounds of formula I may be administered in pharmaceutically acceptable acid addition salt form. Such salts possess the same order of activity as the free bases and are readily prepared in conventional manner. Suitable such salt forms include mineral acid salts, such as the hydrochloride, hydrobromide and sulphate, and organic acid salts, such as the fumarate, maleate, tartrate, methane-, ethaneand benzene-sulphonate, citrate and malate.

The invention also provides a pharmaceutical composition comprising as active agent a compound of formula l, or a pharmaceutically acceptable acid addition salt thereof, in association with a pharmaceutically acceptable carrier or diluent.

In the following illustrative Examples all temperatures are indicated in degrees Centigrade and are uncorrected.

. EXAMPLE 1: cisl ,2,3 ,4,4a, l Ob-Hexahydro-S,9-dimethoxy-2- methyl-6-phenyl-benzo(c)( 1,6)naphthyridine a. g of cis-4-amino-3-(3,4-dimethoxyphenyl)-lmethylpiperidine are dissolved in 30 cc of dioxane and 33 cc of a 2 N caustic soda solution, and a solution of 9 cc of benzoyl chloride in 30 cc of dioxane is added dropwise within minutes at room temperature while stirring. The resulting white crystalline mash is rendered strongly alkaline with a 2 N caustic soda solution, is diluted with water and filtered off. After recrystallization from ethyl acetate cis-4-benzoylamino-3-(3,4- dimethoxyphenyl)-l-methylpiperidine is obtained as white fine crystals having a MP. of l34l35.

b. 18 g of cis-4-benzoylamino-3-(3,4- dimethoxyphenyl)-l-methylpiperidine are boiled under reflux in 100 cc of phosphorus oxychloride for 1 /2 hours. The reaction mixture is subsequently evaporated to dryness in a vacuum and the resulting oily residue is shaken with methylene chloride and a 2 N caustic soda solution. The organic phase is dried over sodium sulphate and concentrated by evaporation. Crystallization from ethyl acetate yields the title compound as almost colourless crystals having a MP. of l26l27.

ln-a manner analogous to Example 1 above, employing the corresponding starting materials, the following compounds are obtained:

l,2,3,4,4u, l ()b-hexahydro-bcnzolc l,6]naphthyridine (M.P. of dihydrochloride 23824()) cis-6-( Z-Fluorphenyl )-8,9-dimcthoxy-2-methyl' 8 cis-6-( 4-Aethoxyphenyl )-8,9-dimethoxy-2- methyl-1,2,3 ,4,4a, l Ob-hexahydro-benzol c][ l,6- ]naphthyridine (M.P. of dihydrochloride 250252) 5 I cis-8,9-Dimethoxy-2-methyl-6-(2,3-

dimethylphenyl l ,2,3,4,4a, l Ob-hexahydro-benzo[c][ l,6]naphthyridine (M.P. of dihydrochloride 250252) cis8,9-Dimethoxy-2-methyl-6-( 3 ,5- dimethylphenyl l ,2,3,4,4a, l Ob-hexahydro-benzo[c][ l,6]naphthyridine (M.P. of dihydrochloride 2l8222) EXAMPLE 2: cis'6-( 3 ,4-Dichlorophenyl l ,2,3 ,4,4a,l Ob-hexahydro- 40 8,9 dimethoxy-2-methyl-benzo[c][ l ,6]naphthyridine cis-4-( 3 ,4-Dichlorobenzoylamino )-3-( 3 ,4- dirnethoxyphenyl l -methylpiperidine [M.P. 134 -4 35, obtained in analogy to Example 1 (a)] is cyclized in analogy to the process described in Example (from ethyl acetate).

EXAMPLE 3: I cis-l ,2,3,4,4a, l Ob-Hexahydro-S,9-dimethoxy-6-( 3,4- dimethoxyphenyl )-2-methyl-benzo[c][ l ,6 ]naphthyridine a. 9.7 g of cis-4-amino-3-(3,4-dimethoxyphenyl)-lmethylpiperidine dihydrochloride are allowed to stand together with 8.3 g of 3,4-dimethoxybenzoyl chloride in 50 cc of dry pyridine at room temperature for 20 hours. 20 cc of water are subsequently added to the reaction mixture while cooling, and this is allowed to stand at' room temperature for a further 30 minutes. The reaction mixture is then diluted with 400 cc of water and 50 cc of a 2 N caustic soda solution, extraction is effected with methylene chloride, the organic phase being dried over sodium sulphate and concentrated by evaporation in a vacuum. The cis-4-(3,4- dimethoxybenzoylamino)-3-( 3,4-dimethoxyphenyl l methylpiperidine is used for the next reaction without further purification. b. cis 4-( 3,4- dimethoxybenzoylamino )-.3-( 3,4-dimethoxyphenyl l 1 (b). The title compound has a MP. of l83- 184.

methylpiperidine is cyclized in accordance with the process described in Example I (b). The title compound has a M.P. of 199201 (from ethyl acetate).

EXAMPLE 4: cis-l ,2,3,4,4a,10b-Hexahydro8,9-dimethoxy-2- methyl-6% 4-nitrophenyl )-benzo[c][ 1,6 ]naphthyridine a. 7.45 g of cis-4-amino-3-(3,4-dimethoxyphenyl)-1- methylpiperidine and 5.55 g of 4-nitrobenzoyl chloride in 50 cc of pyridine are heated to 60 for 3 hours. The reaction mixture is cooled, is rendered strongly alkaline with concentrated caustic soda solution and is gradually diluted with a total of'2OO cc of water, whereby the product is obtained in crystalline form and may be filtered off. After crystallization from ethyl acetate the cis-3-( 3 ,4-dimethoxyphenyl l -methyl-4-( 4- nitrobenzoylamino)-piperidine has a MP. of 167.

b. cis-3-( 3 ,4-Dimethoxyphenyl 1 -methyl-4-( 4- nitrobenzoylamino)-piperidine is cyclized in analogy to the process described in Example 1 (b). The title compound has a M.P. of 194195 (from ethyl acetate).

EXAMPLE 5: cis-6-(4-Aminophenyl)1,2,3,4,4a,10b-hexahydro-8,9- dimethxy-2-methyl-benzo[c][ 1,6 ]naphthyridine 2.7 g of iron turnings are added to a hot solution of 2.0 g. of cis-1,2,3,4,4a,lOb-hexahydro-8,9-dimethoxy- 2-methyl-6-(4-nitrophenyl )-benzo[c][ 1,6 ]naphthyridine in 40 cc of ethanol and 13 cc of water. A mixture of 13 cc of ethanol, 3 cc of water and 0.7 cc of 2 N hydrochloric acid is added dropwise within 40 minutes while heating, and the reaction mixture is boiled under reflux for a further 3 hours. 1 cc of a 2 N caustic soda solution is then added, filtration is effected and the filtrate is concentrated by evaporation in a vacuum. The residue is dissolved in chloroform, the solution is dried over sodium sulphate, filtered and concentrated by evaporation in a vacuum. The residue is crystallized from ethyl acetate, whereby yellowish prismshaving a M.P. of 168l70, are obtained.

In a manner analogous to Example above, employing the corresponding starting materials, the following compounds are obtained:-

- cis-6-( 3-Aminophenyl )-8,9-dimethoxy2-methyl- 1,2,3,4,4a,l0b-hexahydro-benzo[c][1,6]naphthyridine (M.P. of trihydrochloride 268270) cis-6-( 2-Aminophenyl )-8,9-dimethoxy-2-methyll ,2,3,4,4a,10b-hexahydro-bcnzo[c'][ 1,6]naphthyridine (M.P. 174175) EXAMPLE 6: cis-6-(4-Acetamidophenyl)-1,2,3 ,4,4a, l Ob-hexahydro- 8,9-dimethoxy 2-methylbenzo[c][ 1,6]naphthyridine 1.0 g of cis-6-(4-aminophenyl)-l,2,3,4,4a,10hhexahydro-8,9-dimethoxy-2-methyl-benzo[c][ 1,6- ]naphthyridine (produced as in Example 5) is heated to 60 in a mixture of2 cc of pyridine and 2 cc of acetic anhydride for 2 hours. The reaction mixture is then evaporated to dryness in a vacuum and the residue is crystallized from acetone. M.P. 173175.

EXAMPLE 7: cis-8,9-Dimethoxy-2-methyl-6-( 4- pivaloylaminophenyl 1 ,2,3,4,4u, lOb-hexahydro-benzo[c][ 1,6]naphthyridine 2 g of 6-(4aminophenyl)-8,9-dimethoxy-2-methyl- 1,2,3,4,-4u,10b-hexahydro-benzolc][ 1,6 ]naphthyridine, 10 ml of pyridine and 6 ml of pivalic acid anhydride areheated at 60 for 2 hours. The reaction mixture is then treated with 10 ml of water and evaporated to dryness under vacuum. The resulting oily residue is dissolved in ethanol and treated with a small excess of ethanolic hydrochloric acid, whereby the dihydrochloride of the title compound crystallizes out in yellowish prisms of M.P. 245.

EXAMPLE 8: cis- 6-( 4-Benzoylaminophenyl )-8 ,9-dimethoxy-2 methyl- 1 ,2,3,4,4a, 1 Ob-hexahydro-benzo[c][ 1,6]naphthyridine 2 g of 6-(4-aminophenyl)-8,9-dimethoxy-2-methyl- 1,2,3,4,-4a, lOb-hexahydro-benzo[c] 1 ,6]naphthyridine are dissolved in 30 ml of pyridine, 1 g of benzoylchloride is added to the solution and the reaction mixture is allowed to stand at room temperature for 15 hours. The reaction mixture is then treated with 10 ml of water, allowed to stand for 10 minutes and is then reduced in volume under vacuum. The resulting residue is rendered alkaline with dilute sodium hydroxide and is then extracted with methylenechloride. After evaporating off of the organic phase, the crude product is dissolved in ethanol and rendered acid with an ethanolic hydrochloric acid solution, whereby the dihydro chloride of the title compound crystallizes out in yellowish prisms of M.P. 240-245.

EXAMPLE 9: cis-6-( 3-Benzoylaminophenyl )-8,9dimethoxy-2- methyl- 1 ,2,3,4,4a, l Ob-hexahydro-benzo[c] 1,6]naphthyridine 2 g of cis-6-(3aminophenyl)-8,9-dimethoxy-2- methyl-1,2,3,4,4a,10b-hexahydro-benzolc][ 1,6]naphthyridine are dissolved in 30 ml of pyridine, 1 g of benzoylchloride is added and the reaction mixture is allowed to stand for 15 hours at room temperature. The reaction mixture is treated with 10 ml of water, allowed to stand for 10 minutes and is then reduced in volume under vacuum. The resulting residue is rendered alkaline with diluted sodium hydroxide and is then extracted with methylenechloride. After evaporating off of the organic phase, the crude product is dissolved in ethanol and rendered acid with an ethanolic hydrochloric acid solution, whereby the dihydrochloride of the title compound crystallizes out in yellow crystals of M.P. 247-250.

In a manner analogous to Example 6 to 9 above, acyl' ation is effected by reaction of a cis-6-(aminophenyl)- 1,2,3 ,4,4a,10b-hexahydro-8 ,9-dimethoxy-2-methylbenzo[c][ 1,6]naphthyridine, or a cis6-(aminophenyl)- 1,2,3 ,4,4a, 1 Ob-hexahydro-8,9-methylenedioxy-2- methylbenzo[c][ 1,6]naphthyridine, or a cis-6- (aminophenyl )-l ,2,3,4,4a, l Ob-hexahydro-2-methylbenzo[c][ l ,6]naphthyridine, with the chloride or anhydride'of aceticacid, propionic acid, stearic acid, phenacetic. acid, 2,4-dimethyl-phenacetic acid, 3,5-dimethoxy-phenacetic acid, 2-fluoro or 2-chloro or 2-bromo benzoic acid, cinnamic acid, nicotinic acid, 3- thiophene carboxylic acid, 3-furan carboxylic acid, or with 2-pyrrole carboxylic acid anhydridc, to obtain the corresponding 2-, 3- or 4 acylamino naphthyridine. Examples of compounds obtained are:-

cis-6-( 3-Acetanilido )-8,9-dimethoxy-2methy1- 1,2,3.4,4a, l (lb-hexahydro-benzolcfl 1,6]naphthyridine (M.P. of dihydrochloride 268-270) EXAMPLE l: cisl ,2,3 ,4,4a, l Ob-Hex ahydro-6-( 3,5- dimethoxyphenyl )2-methyl-benzo[c][ l ,6]naphthyridine cis-4-( 3 ,5-Dimethoxybenzoylamino)-1-methyl-3 phenylpiperidine [M.P. l23l 24, obtained in analogy to Example l2(a) hereinafter] is cyclized in analogy to the process described in Example 1(1)). The title com pound has a MP. of l23l24 (from ethyl acetate)...

EXAMPLE 1'1: cis-l ,2,3 ,4,4a, l Ob-Hexahydro-8,9-dimethoxy-2- methyl-6-( p-tolyl )-benzo[c][ 1,6]naphthyridine.

7.35 g of cis-3-(3,4-dimethoxyphenyl)-l-methyl-4- (4 toluoylamino)-piperidine [M.P. l45l46, obtained in analogy to Example 1(a)] and 35 cc of phosphorus oxychloride are reacted as described in Example 1(b). The residue obtained after evaporation of the solvent is dissolved in 200 cc of acetone. After the addition of 8.5 cc of 5 N solution of hydrochloric acid in ethanol, the dihydrochloride of the title compound is obtained. M.P.. 257.

EXAMPLE 1 2: cisl ,2,3 ,4,4a, l Ob-Hexahydro-8,9-dimethoxy-6- (4-methoxyphenyl 2-methyl-benzo[c][ l,6]naphthyri dine.

cis-4-(4-Methoxybenzoylamino)-3-(3,4-dimethoxyphenyl)l-methylpiperidine [M.P. 223226, obtained in analogy to Example 1(a)] is cyclized in analogy to the process described in Example 8. The dihydrochloride of the title compound has a MP. of 250-252 (from ethanol). 7 i

EXAMPLE 1 3: cis-6-(4Chlorophenyl l ,2,3,4,4a, l Ob-hexahydro-8,9- dimethoxy-2-methyl-benzolc][ 1,6 lnaphthyridine.

cis-4 -(4 Chlorobenzoylamino)-3-(3,4- dimethoxyphenyl l -methylpiperidine [crude product, obtained in analogy to Example 1(a)] is cyclized in analogy to the process described in Example 8. The dihydrochloride of the title compound has a M.P. of 245 (from ethanol).

Y 0 EXAMPLE l4: cis-6-( 2Chlorophenyl )-l ,2,3,4,4a, l Ob-hexahydro-8,9- dimethoxy-2methyl-benzolc][ 1,6 ]naphthyrid ine.

cis-4-(ZChlorobenzoylamino)-3-( 3,4- dimethoxyphenyl l -methylpipcridine [crude product, obtained in analogy to Example 1(a)] is cyclized in analogy to the process described in Example 8. The dihydrochloride of the title compound has a M.P. of 223 2 26 (from ethanol).

u EXAMPLE l5: cis-6-( 4-Fluorophenyl l ,2,3,4,4a, l0b-hexahydro-8,9- dimethoxy-2-methyl-benzo[c][ l ,6]naphthyridinei u. A solution of 6 g of cis-4-amino-3-(3,4- dimethoxyphenyl)-l-methylpiperidine and 4.6 g of 4- fluorobenzoyl chloride in 50 cc of pyridine is heated at for 3 hours. The reaction mixture is strongly concentrated under vacuum, water is added, and the mixture is allowed to stand at room temperature for 1 hour. The reaction mixture is" rendered strongly alkaline with dilute potassium carbonate solution and the aqueous phase is extracted thrice with chloroform. The organic phases are combined, dried over sodium sulphate and concentrated by evaporation in a vacuum. The residue is crystallized from ethyl acetate/pentan'e (1:1 by volume), whereby the pure cis-4-(4-fluorobenzoylamino)- 3(3,4-dimethoxyphenyl)-l-methylpiperidine is obtained as yellowish prisms having a M.P. of l30-l 32.

b. v cis-4-(4-Fluorobenzoylamino)-3-(3,4- dimethoxyphenyl)-l-methylpiperidine is cyclized in analogy to the process described in Example 8. The dihydrochloride of the title compound has a M.P. of 250-255 (from ethanol).

EXAMPLE l6: cis-l,2,3,4,4a,10bHexahydro-8,9-dimethoxy-2- methyl6-( 4-methylthiophenyl)-benzo[c][ l ,6]naphthyridine cis-3-(3,4-Dimethoxyphenyl)-l-methyl-4-(4- methylthiobenzoylamino )-piperidine [M.P. l44l 46, obtained in analogy to Example 4(a(] is cyclized in analogy to the )]described in Example 8. The dihydrochloride of the title compound has a M.P. of 227-230 (from ethanol/acetone).

EXAMPLE l7: eis-l ,2,3,4,4a, l Ob-Hexahydro-8,9-dimethoxy-2- methyl6-( 4-nitrophenyl )benzo[c][ l ,6]naphthyridine cis-3-( 3 ,4-Dimethoxyphenyl l -methyl-4-( 4- nitrobenzoylamino)-piperidine [M.P. 167, see Example 4(a)] is cyclized in analogy to the process described in Example 8. The dihydrochloride of the title compound has a m.p. of 225-230 (from ethanol).

EXAMPLE 1 8: cis-l ,2,3,4,4a, lOb-Hexahydro-2-methyl-6-phenyl-benzolcll l ,6lnaphthyridine cis-4-Be'nzoylaminol-methyl-3-phenylpiperidine [M.P. l54-l 55, obtained in analogy to Example 4(a)] is cyclized in analogy to the process described in Example 8. The dihydrochloride of the title compound has a M.P. of 243-244 (from ethanol).

EXAMPLE 19: cis-l ,2,3 ,4,4u, l ()h-Hexahydro-6-(4-methoxyphenyl )-2- methyl-benzol c'][ l ,6 lnaphthyridine cis-4-( 4-Methoxybenzoylamino l -methyl-3- phenylpiperidine [M.P. ll 66, obtained in analogy to Example l2(a)] is cyclized in analogy to the process described in Example 8. The dihydrochloride of the title compound has a M.P. of 26927() (from ethanol);

EXAMPLE 20: cis-l 2.3.4.411, l hHcxahydro-6( 3,4- dimethoxyphenyl )-2-methyl-henzol ('ll 1,6 ]naphthyridine cis-4-( 3,4-Dimethoxybenzoylamino l -methyl-3- phenylpiperidine [M.P. l53l55, obtained in analogy to Example l2(a)] is cyclized in analogy to the process described in Example 8. The dihydrochloride of the title compound has a MP. of 220222 (from ethanol).

EXAMPLE 2 l: cis-6-( 3-Trifluoromethylphenyl l .2,3,4,4a, l 012- hexahydro8,9-dimethoxy-Z-methyI-benzolc][ 1,6-

lnaphthyridine cis-4-( 3Trifluoromethyl-benzoylamino )-3-( 3 ,4- dimethoxyphenyl l -methylpiperidine [M.P. l22l24, obtained in analogy to Example l2(u)] is cyclized in analogy to the process described in Example 8. The dihydrochloride of the title compound has 21 MP. of 2l5-2l7 (from ethanol).

EXAMPLE 22:

, cis-l ,2,3,4,4u, l 0b-Hexahydro-2-methyl-8,9 methylenedioxy-6-phenyl-benzo[c][ l ,6]naphthyridine u. 5.0 of cis-4-amino-3-( 3,4- methylenedioxyphenyl 1 -methylpiperidine are dissolved in 50 cc of chloroform, and a solution of 3.3 g of benzoyl chloride in IQ cc of chloroform is added at 0. The reaction solution is allowed to stand at room temperature for 2 hours and is extracted with a saturated potassium carbonate solution and subsequently with water. The chloroform layer is dried over sodium sulphate and concentrated by evaporation. The residue is recrystallized from acetone. The cis-4-benzoylamino- 3-( 3 .4-methylenedioxyphenyl l -methylpiperidine has a MP. of l75-l77.

b. 7.0 g of cis-4-benzoylamino-3-( 3,4- methylenedioxyphenyl l -methylpiperidine are heated to 90 in 75 cc of phosphorus oxychloride for hours. The reaction mixture is subsequently evaporated to dryness, the residue is dissolved in 50 cc of ice water and a saturated potassium carbonate solution is added until the mixture is strongly alkaline. The reaction mixture is extracted with chloroform, and the chloroform mixture is washed with water, dried over sodium sul phate, and the solvent is evaporated. The residue is taken up in 20 cc of ethanol, and absolute hydrochloric acid in ethanol is added until an acid reaction to Congo red is obtained and precipitation is effected with ether. The precipitate, the dihydrochloride of the title compound, is recrystallized from ethanol/ether. Yellow coloured crystals having a MP. of 248 (decomp.).

EXAMPLE 23: cisl 2.3.4.411, l ()h-Hexahydro-6-( 3,4- dimethoxyphenyl )2-methyl-8,9-methylenedioxy-benzo[(']l 1,6]naphthyridine 8.0 g of crude cis-4-( 3.4-dimethoxybenzoylamino )-3- (3.4-mcthylenedioxyphenyl l -methylpiperidine [crude product, obtained in analogy to Example 19((1) are heated to 90 in 75 cc of phosphorus oxychloride for l8 hours. The phosphorus oxychloride is subsequently distilled off and the resulting residue is taken up in water. The reaction solution is rendered alkaline with an excess of a saturated potassium carbonate solu tion and extraction is effected with chloroform. The chloroform layer is washed with water, dried over sodium sulphate and concentrated by evaporation. The dark residue is dissolved in ethanol and an excess of maleic acid is added. The yellow coloured bis-hydro gen maleate of the title compound crystallizes upon cooling and has 21 MP. of l93l 94 after recrystallization from methanol.

EXAMPLE 24: cis-8,9-Dimethoxy-2-methyl-6-( 3 ,4-dimethylphenyl l ,2,3,4,4a, l Ob-hexahydro-benzolc][ 1,6]naphthyridine cis-3-( 3 ,4-Dimethoxyphenyl 1 -.methyl-4-( 3,4- dimethylbenzoylamino)-piperidine is cyclized in analogy to the process described in Example 1(b). The bishydrogen maleate of the title compound has a M.P. of l 82l 84 (from ethanol).

EX A M P LE 25 Cis-6-( 4-forrnamidophenyl )-8 ,9-dimethoxxy-2-methyll ,2,3,4,4a, l Oh-hexahydro-benzo[c][ l ,6]naphthyridine EXAMPLE 26: Cis-6-( 3-formamidophenyl )-8,9-dimethoxy-2-methyll,2,3,4,4a, l 0b-hexahydro-benzo[c][ 1,6]naphthyridine 2,6 g of cis-6-(3-aminophenyl)-8,9-dimethoxy-2- methyl- 1 ,2,3,4,4a, l Ob-hexahydro-benzo[c][ l ,6] naphthyridine are heated to 100 for 2% hours in 50 ml of formic acid. The reaction solution is evaporated to dryness in a vacuum, the resulting residue is made alkaline with a dilute potash solution and this aqueous phase is extracted with methylene chloride. After drying and concentrating the organic phase by evaporation, the title compound is obtained as yellowish foam and crystallizes after the addition of acetone in the form of yellowish prisms having a melting point of 2092l0.

EXAMPLE 27: Cis-6-( 4-caproylamidophenyl )-8 ,9-dimethoxy-2- methyl- 1 ,2,3,4,4a, l Ob-hexahydro-benzo[c][ l ,6]naphthyridine The title compound is obtained in a manner analogous to that described in Example 7 by acylation of 6- (4aminophe'nyl )-8,9-dimethoxy-2-methyll,2,3,4,4u, lOIJ-hexahydro-benzoh][ l-,6]naphthyridine with caproyl chloride in pyridine. (Melting point of the dihydrochloride form: 235238, crystallization from ethanol).

EXAMPLE 28: Cis6-( 4-lauroylamidophenyl )-8,9dimcthoxy-2- methyl- 1 ,2,3,4,4u, l ()b-hexahydro-henzol (H l ,6 lnaphthyridine The title compound is obtained in a manner analogous to that described in Example 7 by acylation of 6 (4-aminophenyl )-8 ,9-dimethoxy-2-methyl- 1,2,3 ,4,4a, l Ob-hexahydro-benzo[c][ l ,6]naphthyridine with lauroyl chloride in pyridine. (Melting point of the dihydrochloride form: 2102l5, crystallization from aethanol).

EXAMPLE 29: Cis-8 ,9-dimethoxy-2-methyl-6-( 4- stearoylamidophenyl )-l ,2,3 ,4,4a, lOb-hexahydro-benzo[c][ l ,6]naphthyridine The title compound is obtained in a manner analogous to that described in Example 7 by acylation of 6- (4-aminophenyl )-8,9-dimethoxy-2-methyll ,2,3,4,4c]10b-hexahydro-benzo[c[ l ,6]naphthyridine with stearoyl chloride in pyridine. (Melting point of the dihydrochloride form: 2l5220, crystallization from ethanol).

EXAMPLE 30: Cis-8-9-dimethoxy-2-methyl-6-(4- nonanoylaminophenyl)- 1 ,2,3 ,4 ,4a, 1 Ob-hexahydrobenzo[CJ [1,6] naphthyridine The title compound is obtained in a manner analogous to that described in Example 7 by acylation of 6- (4-aminophenyl)-8,9-dimethoxy-2-methyll ,2 ,3 ,4,4a, l Ob-hexahydro-benzo[c][ l ,6]naphthyridine with nonanoyl chloride. (Melting point of dihydrochloride form: 220225, crystallization from ethanol).

EXAMPLE 3 l: Cis-8,9-dimethoxy-2-methyl-6-( 4- pentanoylaminophenyl)- l ,2,3,4,4a,1OIOb-hexahydrobenzo[c][ 1,6]naphthyridine 3 g of 6-( 4-aminophenyl)-8,9-dimethoxy-2-methyll ,2,3 ,4,4a, l Ob-hexahydro-benzo[c]l 1 ,6 naphthyridine and 6,2 g of valeric acid chloride are heated to the boil under reflux in 70 ml of acetonitrile for 7 hours. The reaction mixture is evaporated to dryness in a vacuum, water is added to the residue, the reaction mixture is made alkaline with potassium carbonate and extracted with methylene chloride. The solution is concentrated by evaporation, the crude product is dissolved in ethanol and a slight excess of hydrochloric acid in ethanol is added, whereby the title compound crystallizes in dihydrochloride form (melting point: 230-235).

EXAMPLE 32: Cis-6-( 4-isobutyroylaminophenyl )-8 ,9-dimethoxy-2- methyl-l ,2,3,4,4a, l 0b-hexahydro-benzo[c][ l ,6]naphthyridine The title compound is obtained in a manner analogous to that described in Example 7 by acylation of 6- 4-aminophenyl )-8 ,9-dimethoxy-2-methyll ,2,3,4,4a, l Ob-hexahydro-benzolcfl l ,6]naphthyridine with isobutyroyl chloride. (Melting point of the dihydrochloride form: 233238, from ethanol).

EXAMPLE 33:

Cis-6-l 6-( 2-furoylamino)phenyl ]-8,9-dimcthoxy-2- methyl-l ,2,3,4,4a, l Ob-hexahydro-benzolc 1,6]naphthyridine The title compound is obtained in a manner analogous to that described in Example 7 by acylation of 6- (4-aminophenyl)-8,9-dimethoxy-2-methyll,2,3,4,4a, l Ob-hexahydro-benzo[c][ l ,6]naphthyridine with Z-furan-carboxylic acid chloride in pyridine (over night at room temperature). After working up and purifying in a manner analogous to that described in Example 3 l the dihydrochloride form of the title compound, having a melting point of 251 255, is obtained.

EXAMPLE 34: Cis-8,9-dimethoxy-2-methyl-4- 4-( 2- thenoylamino )phenyl l ,2,3 ,4,4a, l Ob-hexahydro-benzo[c][ l ,6]naphthyridine The title compound is obtained in a manner analogous to that described in Example 33 by acylation of 6-(4-aminophenyl)-8,9-dimethoxy-2-methyll ,2,3,4,4a,10b-hexahydro-benzo[c][ l ,6]naphthyridine with 2-thiophene carboxylic acid chloride. Melting point of the dihydrochloride form: 246249.

. EXAMPLE 35: Cis-8,9,l02-methyl-6-(4-nicotinoyl-aminophenyl)- l ,2,3,4,4a l Ob-hexahydro-benzo[c][ 1,6]naphthyridine The title compound is obtained in a manner analogous to that described in Example 33 by acylation of 6-(4-aminophenyl)-8,9-dimethoxy-2-methyl- 1 ,2,3 ,4,4a, l 0b-hexahydro-benzo[c][ 1,6 ]naphthyridine with nicotinic acid chloride. (Melting point of the trihydrochloride form: 248-25 1).

EXAMPLE 37:

. Cis-8 ,9-dimethoxy-2-methyl-6-( 4- phenylacetamidophenyl )-l ,2,3,4,4a,10b-hexahydrobenzolc] 1 ,6]naphthyridine 30g of 6-(4-aminophenyl)-8,9-dimethoxy-2-methyll ,2,3 ,4,4a, 1 Ob-hexahydro-benzo[c][ 1,6]naphthyridine and 6,0 g of phenylacetic acid chloride are heated to the boil under reflux in ml of acetonitrile for 7 hours. After working up in a manner analogous to that described in Example 31, and upon adding dilute hydrochloric acid in ethanol to the crude product, the dihydrochloride form of the title compound slowly crystallize s (melting point 240-245 EXAMPLE 38: Cis-6-( 4-cinnamoylaminophenyl )-8,9-dimethoxy-2- methyl- 1 ,2,3,4,4a, l Ob-hexahydro-benzolcll l ,6]naphthyridine The title compound is obtained in a manner analogous to that described in Example 37 by acylation of 6-( 4-aminophenyl )-8 ,9-dimethoxy-2-methyll,2,3,4,4u, l 0h-hexahydro-benzo[c][ l,6 ]naphthyridine with cinnamoyl chloride. (Melting point of the dihydrochloride form: 242246).

The following compounds are produced using the process described in Example 36 and the appropriate starting materials:

Cis-6- 4-( 3-methyl-4-methoxyben2amido )phenyl 8,9-dimethoxy-2-methyl-1 ,2,3,4,4a,l Obhexahydro-benzo[c][ 1,6]naphthyridine.

Cis-6-[4(4-bromobenzamido)phenyl]-8,9-

dimethoxy-2-methyl-1,2,3 ,4,4a,10b-hexahydro benzo[c][ 1,6 ]naphthyridine.

Cis-64-(4-fluorobenzamido)phenyl]-8,9-dimethoxy 2-methyl-l ,2,3,4,4a,l Ob-hexahydro-benzokfl 1,6- ]naphthyridine.

What is claimed is:

1. A compound of the formula:

wherein R is hydrogen, alkyl of one to three carbon atoms, alkoxy of one to three carbon atoms or alkylthio of one to three carbon atoms, fluorine, bromine, chlorine, nitro, trifluoromethyl, amino or -NH-CO-R wherein -CO-R is alkanoyl of 1 to 18 carbon atoms, benzoyl, benzoyl wherein the benzene ring is substituted by one X and one Y, X being lower alkyl of one to four carbon atoms, lower alkoxy of one to four carbon atoms, fluorine, chlorine, or bromine, and Y being hydrogen, lower alkyl of one to four carbon atoms, lower alkoxy of one to four carbon atoms, or chlorine, phenyl-alkenoyl, wherein the alkylene section has one to three car bon atoms, cinnamoyl, phenyl-alkenoyl as defined above or cinnamoyl which are substituted in the benzene ring by one X and one Y which are as defined above, or A-CO, A being thienyl, furyl, pyrrolyl, or pyridyl R is hydrogen, chlorine, alkyl of one to three carbon atoms or alkoxy of one to three carbon atoms, and

R and R are both hydrogen or both methoxy, or

R and R together are methylenedioxy,

or a pharmaceutically acceptable acid addition salt thereof.

2. The compound of claim 1, which is cis- 1 ,2,3,4,4a,10h-Hexahydro-8,9-dimethoxy-2- methyl-6-phenyl-benzo[c][ 1,6]naphthyridine.

3. The compound of claim 1, which is cis-6-(3,4-

Dichlorophenyl)-1,2,3,4,4a,lOb-hexahydro-8,9 climethoxy-Z-methyl-benzolc][ 1,6]naphthyridine.

4. The compound of claim 1, which is cis-l ,2,3,4,4u,1Ob-Hexahydro-8,9dimethoxy-6-(3,4 dimethoxyphenyl )-2-methyl-benzol c 1,6]naphthyridine.

S. The compound of claim 1, which is cis-l ,2,3,4,4u,10h-Hexahydro-8,9dimethoxy-2- methyl-6-(4-nitropheny1)-benzo[c] l ,6]naphthyridine. 6. The compound of claim 1, which is cis-6( 4-Aminopheny1 )-1 ,2,3 ,4,4a, lOb-hexahydro- 8,9-dimethoxy-Z-methyl-benzo[c][ 1 ,6 ]naphthyridine.

7. The compound of claim 1, which is cis-6-(4-Acetamidophenyl-1 ,2,3,4,4a, l Obhexahydro-8,9-dimethoxy-2-methy1-benzo[c][ 1,6- ]naphthyridine.

8. The compound of claim 1, which is cisl ,2,3,4,4a, l Ob-Hexahydro-6-( 3,5-

dimethoxyphenyl)-2-methyl-benzo[c][ 1,6]naphthyridine.

9. The compound of claim 1, which is cis- 1 ,2,3,4,4a, l Ob-Hexahydro-S,9-dimethoxy-2- methyl6(p-tolyl )-benzo[c][ 1,6]naphthyridine.

10. The compound of claim 1, which is cis-1,2,3 ,4,4a, 1 ObHexahydro-8,9-dimethoxy-6( 4- methoxy-pheny])-2-methyl-benzo[c][ 1,6]napthyridine.

11. The compound of claim 1, which is cis-6-(4-Chlorophenyl)-l ,2,3,4,4a,10b-hexahydro- 8,9-dimethoxy-2methyl-benzo[c][ 1 ,6]naphthyri dine.

12. The compound of claim 1, which is cis-6-(2-Chlorophenyl)-1,2,3,4,4a,IOb-hexahydro- 8,9-dimethoxy-2-methyl-benzo[c]l 1,6]naphthyridine.

13. The compound of claim 1, which is cis-6(4-Fluorophenyl l ,2,3,4,4a, 1 Ob-hexahydro- 8,9-dimethoxy-2-methyl-benzo[c][ 1 ,6]naphthyridine.

14. The compound of claim 1, which is cis-l ,2,3,4,4a,10h-Hexahydro-S,9-dimethoXy-2- methyl-6-(4-methylthiophenyl )-benzo[c][ 1,6- ]naphthyridine.

15. The compound of claim 1, which is cis- 1 ,2,3 ,4,4a,1 0b-Hexahydro-2-methyl-6- phenylbenzo[c][ l ,6lnaphthyridine.

16. The compound of claim 1, which is cis-a, lOba,l0b,-Hexahydro-6-(4-methoxyphenyl )-2- methyl-benzo[c][ 1 ,6]naphthyridine.

17. The compound of claim 1, which is cis-l ,2,3 ,4,4a, l Ob'Hexahydro-6-( 3 ,4-

dimethoxyphenyl )-2-methyl-benzo[c][ 1,6]naphthyridine.

18. The compound of claim 1, which is cis-6-( 3-Trifluoromethylphenyl )-l ,2,3,4,4a, l Obhexahydro-8,9-dimethoxy-2-methyl-benzo[c][ l ,6 ]naphthyridine.

19. The compound of claim 1, which is cis-l ,2,3 ,4,4a, l ()b-Hexahydro-2-methyl-8,9-

methylenedioxy-6-phenyl-benzo[c][ 1,6 ]naphthyridine.

20. The compound of claim 1, which is cis-l ,2,3,4,4a,10b-Hexahydro-6-(3,4-

dimethoxyphenyl )-2-methyl-8,9-methylenedioxybenzo[ c][ 1,6 ]naphthyridine.

21. The compound of claim 1, which is cis-8,9-Dimethoxy-2-methyl-6-( 3,4-

dimcthylphcnyl l ,2,3,4,4a, l Oh-hexahydro-benzo[c][ 1,6]naphthyridine.

22. The compound of claim 1, which is cis-6-( 2-Flurophenyl )8 ,9-dimethoxy-2srnethyll,2,3,4,4a,10b-heXahydro-bcnzo[c][ l ,6]naphthyridine.

23. The compound of claim 1, which is cis-6-( 4-Aethoxyphenyl )-8 ,9-dimethoxy-2-methyll ,2,3 ,4,4a, l Ob-hexahydro-benz o[c][ 1 ,6]naphthyridine.

24. The compound of claim 1, which is cis-8,9-Dimethoxy-2-methyl-6-(2,3-

dimethylphenyl )-l ,2,3 ,4,4a, 1 Ob-hexahydro-ben- 1O zo[c][l,6]naphthyridine.

25. The compound of claim 1, which is cis-8,9-DimethoXy-2-methyl-6-( 3 ,5-

dimethylphenyl )-1 ,2,3 ,4,4a, l Ob-hexahydro-benzo[c][l,6]naphthyridine.

26. The compound of claim 1, which is cis-8 ,9-Dimethoxy-2-methyl- 6-( 2,4-

dimethylphenyl )-1 ,2,3 ,4,4a, l Ob-hexahydro-benzo[c][ l ,6]naphthyridine.

27. The compound of claim 1, which is cis- 8 ,9-Dimethoxy-6-( 2,3 -dimethoxyphenyl )-2- methyl-l ,2,3,4,4a, l Ob-hexahydro-benzo[c][ 1,6- ]naphthyridine.

28. The compound of claim 1, which is cis-8 ,9-Dimethoxy-6-( 3 ,5-dimethoxyphenyl )-2- methyl-1,2,3,4,4a,lOb-hexahydro-benzo[c][1,6- ]naphthyridine.

29. The compound of claim 1, which is cis-8,9 Dimethoxy-2-methyl-6-( 3-methyl-4- nitropheny1)-l ,2,3 ,4,4a, 1 Ob-hexahydro-benzo[c][ l ,6]naphthyridine.

30. The compound of claim 1, which is cis-6-( 4-Chloro-3-nitrophenyl)-8,9-dimethoxy-2- methyl- 1 ,2,3,4,4a, lOb-hexahydro-benzo[c][ 1,6- ]naphthyridine.

31. The compound of claim 1, which is cis-8,9Dimethoxy-2-methyl-6-(4-methyl-3- nitrophenyl )-l ,2,3 ,4,4a, lOb-hexahydro-benzo[c][ 1,6]naphthyridine.

32. The compound of claim 1, which is cis- 6-( 3-Aminophenyl )-8 ,9'dimethoxy-2-methyl- 1,2,3,4,4a,lOb-hexahydro-benzo[c][1,6]naphthyridine.

33. The compound of claim 1, which is cis- 6-( Z-Aminophenyl )-8 ,9-dimethoxy-2-methyl- 1,2,3 ,4,4a, 10b-hexahydro-benzo[c] 1,6]naphthyridine.

34. The compound of claim 1, which is cis-6-( 3-Acetanilido )-8 ,9-dimethoxy-2-methyll,2,3,4,4a,lOb-hexahydro-benzo[c][ 1,6]naphthyridine.

35. The compound of claim 1, which is ci s-8,9-Dimethoxy-2methyl-6-(4- propionylaminophenyl )-l ,2,3 ,4,4a, l Ob-hexahydrobenzo[c][ 1,6]naphthyridine.

36. The compound of claim 1, which is cis-8,9-Dirnethoxy-2-methyl-6-(4- pivaloylaminophenyl l ,2,3,4,4a,]Ob-hexahydrobenzolcll 1,6]na'phthyridine.

37. The compound of claim 1, which is cis-6-( 4-Benzoylaminophenyl )8,9-dimethoxy-2- methyl- 1 ,2,3,4,4a, lOb-hexahydro-benzolcfl l ,6- ]naphthyridine'. 5,1"

38. The compound of claim 1, which isv 3 cis-6-( 3-Benzoylaminophcnyl )-8,9-dimethoxy- 2- methyl-l ,2,3,4,4a,10b-hexahydro-benzo[c]['1,6- ]naphthyridine.

39. The compound of claim 1, which is cis -6-( 4-Forrnamidophenyl )-8 ,9-dimethoxy-2- methyl-l ,2,3 ,4,4a,1 0b-hexahydro-benzo[c][ l ,6- ]naphthyridine.

40. The compound of claim 1, which is cis-6-( 3-Formamidophenyl)-8 ,9-dimethoxy-2- methyl- 1 ,2,3,4,4a, l Ob-hexahydro-benzo[c][ l ,6-

, ]naphthyridine.

41. A compound of claim 1, wherein the radical ACO is selected from stearyl, phenacetyl, 2,4-dimethylphenacetyl, 3,5-dimethoxy-phenacetyl, 2-fluoroor 2-chloro or 2-bromo-benzoyl, cinnamoyl, nicotinoyl, 3-thenoyl, 3-furoyl and 2-pyrroyl.

42. A compound of claim 1, wherein R is hydrogen, alkyl of one to threecarbon atoms, alkoxy of one to three carbon atoms or alkylthio of one to three carbon atoms, fluorine, bromine, chlorine, nitro, trifluoromethyl, amino or amido of two to four carbon atoms, R is hydrogen, chlorine, alkyl of one to three carbon atoms or alkoxy of one to three carbon atoms, and R and R are both hydrogen or methoxy, or R and R together are methylenedioxy, or a pharmaceutically acceptable acid addition salt thereof.

43. A compound of claim 1 of the formula:

wherein R is hydrogen, alkyl of one to 17 carbon atoms, thienyl, furyl, pyrrolyl, pyridyl or wherein A is a direct bond, alkylene of one tothree carbon atoms or vinylene, X is hydrogen, alkyl of one to four carbon atoms, alkoxy of one to four carbon atoms, fluorine, chlorine or bromine, and Y is hydrogen, alkyl of one to four carbon atoms or alkoxy of one to four carbon atoms 44. A compound of claim 43, wherein R is hydrogen. 45. A compound of claim43, wherein R is alkyl of l to 17 carbon atoms.

46. A compound of claim 43, wherein R is furyl,,thienyl, pyrrolyl, or pyridyl.

47. A compound of claim 43, wherein A is a bond, alkylene or vinylene.

48. A compound of claim 43, wherein R is alkyl of one tothree carbon atoms.

49.A compound of claim 43, of the formula.

E 3 (N CH3O l N CH3O NHCOR' wherein R is hydrogen, isopropyl, alkyl of l to 17 carbon atoms, furyl, thienyl or pyridyl, or phenyl, styryl or benzyl substituted by one X and one Y, wherein X is hydrogen, methyl, methoxy, fluorine, chlorine or bromine, and Y is hydrogen, methyl or methoxy.

50. A compound of claim 49, wherein R is hydrogen.

5]. The compound of claim 43, which is Cis-6- 4caproylaminophenyl )-8,9dimethoxy-2- methyl-1,2,3,4,4u,lOb-hexahydro-benzo[c][1,6- ]naphthyridine.

52. The compound of claim 43, which is Cis-6-(4-lauroylamidophenyl)-8,9-dimethoxy-2- methyl- 1 ,2,3,4,4a 1-hexahydro-benzo[c][ 1,6- ]naphthyridine.

53. The compound of claim 43, which is Cis-8,9-dimcthoxy-2-methyl'6-(4- stearoylamidophenyl l ,2,3,4,4a, l Ob-hexahydrobenzo[c]{ 1,6]naphthyridine.

54. The compound of claim 43, which is Cis-S,9-dimethoxy-2methyl-6-(4- nonanoylaminophenyl l ,2,3 ,4,4a, l Ob-hexahydrobenzolcll1,6]naphthyridine.

55. The compound of claim 43, which is Cis-8,9-dimethoxy-2-methyl-6-(4- pentanoylaminophenyl l ,2,3,4,4a, l Obhexahydro-benzo[c][ 1,6]naphthyridine.

56. The compound of claim 43, which is Cis-6-(4-isobutyroylaminophenyl)-8,9-dimethoxy-2- methyl- 1 ,2,3,4,4a l Ob-hexahydro-benzo[c][ 1,6- ]naphthyridine.

57. The compound of claim 43, which is Cis-6-[4-( Z-furoylamino )phenyl ]-8,9-dimethoxy-2- methyl- 1 ,2,3,4,4a, l 0b-hexahydro-benzo[c][ 1,6- ]naphthyridine.

58. The compound of claim 43, which is Cis-8,9-dimethoxy-2-methyl-4-[4-(2- thenoylamino)phenyl]- l ,2,3,4,4a, lOb-hexahydrobenzo[c][ l ,6]naphthyridine.

59. The compound of claim 43, which is Cis-8,9dimethoxy-2-methyl-6-(4- nicotinoylaminophenyl)-l ,2,3,4,4a,10bhexahydro-benzo[c][ 1,6]naphthyridine.

60. The compound of claim 43, which is Cis-6-[4-(4-chlorobenzamido)phenyl]-8,9-

dimethoxy-2-methyl-1 ,2,3,4,4a, 1 Ob-hexahydrobenzo[c 1,6]naphthyridine.

61. The compound of claim 43, which is Cis-8,9-dimethoxy-2-methyl'6-( 4- phenylacetamidophenyl l ,2,3 ,4,4a, 10bhexyhydro-benzo[c] l ,6]naphthyridine.

62. The compound of claim 43, which is Cis-6-(4-cinnamoylaminophenyl)-8,9-dimethoxy-2- methyl 1 ,2,3 ,4,4a, l Ob-hexahydro-benzo[c][ 1,6- ]naphthyridine.

63. The compound of claim 43, which is Cis-6-[4-( 3-methyl-4-methoxybenzamido )phenyl 8,9-dimethoxy-2-methyl-1 ,2,3,4,4a, 10bhexahydro-benzo[c][ 1 ,6]naphthyridine.

64. The compound of claim 43, which is Cis6-[4(4-bromobenzamido)phenyl]-8,9-

dimethoxy-2-methyll ,2,3,4,4a,10b-hexahydrobenzo[c][ 1,6]naphthyridine.

65. The compound of claim 43, which is Cis-6-[4-(4-fluorobenzamido)phenyl]-8,9-

dimethoxy-2-methyl- 1 ,2,3 ,4,4a, 1 Ob-hexahydrobenzo[c][ 1,6]naphthyridine.

66. A compound of claim 1, wherein R is hydrogen,

alkyl, alkoxy, alkylthio, fluorine, bromine, chlorine, nitro or trifluoromethyl.

67. A compound of claim 66, wherein R is hydrogen,

chlorine or alkoxy.

68. A compound of claim 1, wherein R is amino. 69. A compound of claim 1, wherein R is acetamido. 70. A compound of claim 1, wherein R is hydrogen. 

1. A COMPOUND OF THE FORMULA.
 2. The compound of claim 1, which is cis-1,2,3,4,4a,10b-Hexahydro-8,9-dimethoxy-2-methyl-6-phenyl -benzo(c)(1,6)naphthyridine.
 3. The compound of claim 1, which is cis-6-(3,4-Dichlorophenyl)-1,2,3,4,4a,10b-hexahydro-8,9-dimethoxy-2-methyl -benzo(c)(1, 6)naphthyridine.
 4. The compound of claim 1, which is cis-1,2,3,4,4a,10b-Hexahydro-8,9-dimethoxy-6-(3,4-dimethoxyphenyl)-2-methyl -benzo(c)(1,6)naphthyridine.
 5. The compound of claim 1, which is cis-1,2,3,4,4a,10b-Hexahydro-8,9-dimethoxy-2-methyl-6-(4-nitrophenyl) -benzo(c)(1,6)naphthyridine.
 6. The compound of claim 1, which is cis-6-(4-Aminophenyl)-1,2,3,4,4a,10b-hexahydro-8,9-dimethoxy-2-methyl -benzo(c)(1,6)naphthyridine.
 7. The compound of claim 1, which is cis-6-(4-Acetamidophenyl-1,2,3,4,4a,10b-hexahydro-8,9-dimethoxy-2-methyl -benzo(c)(1,6)naphthyridine.
 8. The compound of claim 1, which is cis-1,2,3,4,4a,10b-Hexahydro-6-(3,5-dimethoxyphenyl)-2-methyl -benzo(c)(1,6)naphthyridine.
 9. The compound of claim 1, which is cis-1,2,3,4,4a,10b-Hexahydro-8,9-dimethoxy-2-methyl-6-(p-tolyl) -benzo(c)(1,6naphthyridine.
 10. The compound of claim 1, which is cis-1,2,3,4,4a,10b-Hexahydro-8,9-dimethoxy-6-(4-methoxy-phenyl)-2-methyl -benzo(c)(1,6napthyridine.
 11. The compound of claim 1, which is cis-6-(4-Chlorophenyl)-1,2,3,4,4a,10b-hexahydro-8,9-dimethoxy-2-methyl -benzo(c)(1,6)naphthyridine.
 12. The compound of claim 1, which is cis-6-(2-Chlorophenyl)-1,2,3,4,4a,10b-hexahydro-8,9-dimethoxy-2-methyl -benzo(c)(1,6)naphthyridine.
 13. The compound of claim 1, which is cis-6-(4-Fluorophenyl)-1,2,3,4,4a,10b-hexahydro-8,9-dimethoxy-2-methyl -benzo(c)(1,6)naphthyridine.
 14. The compound of claim 1, which is cis-1,2,3,4,4a,10b-Hexahydro-8,9-dimethoxy-2-methyl-6-(4-methylthiophenyl) -benzo( c)(1,6)naphthyridine.
 15. The compound of claim 1, which is cis-1,2,3,4,4a,10b-Hexahydro-2-methyl-6-phenylbenzo( c)(1, 6)naphthyridine.
 16. The compound of claim 1, which is cis-a,10ba,10b,-Hexahydro-6-(4-methoxyphenyl)-2-methyl -benzo(c)(1,6)naphthyridine.
 17. The compound of claim 1, which is cis-1,2,3,4,4a,10b-Hexahydro-6-(3,4-dimethoxyphenyl)-2-methyl-benzo(c)( 1,6)naphthyridine.
 18. The compound of claim 1, which is cis-6-(3-Trifluoromethylphenyl)-1,2,3,4,4a,10b-hexahydro-8,9-dimethoxy-2 -methyl-benzo(c)(1,6)naphthyridine.
 19. The compound of claim 1, which is cis-1,2,3,4,4a,10b-Hexahydro-2-methyl-8,9-methylenedioxy-6-phenyl -benzo(c)(1,6)naphthyridine.
 20. The compound of claim 1, which is cis-1,2,3,4,4a,10b-Hexahydro-6-(3,4-dimethoxyphenyl)-2-methyl-8, 9-methylenedioxy-benzo(c)(1,6)naphthyridine.
 21. The compound of claim 1, which is cis-8,9-Dimethoxy-2-methyl-6-(3,4-dimethylphenyl)-1,2,3,4,4a, 10b-hexahydro-benzo(c)(1,6)naphthyridine.
 22. The compound of claim 1, which is cis-6-(2-Flurophenyl)-8,9-dimethoxy-2-methyl-1,2,3,4,4a,10b-hexahydro -benzo(c)(1,6)naphthyridine.
 23. The compound of claim 1, which is cis-6-(4-Aethoxyphenyl)-8,9-dimethoxy-2-methyl-1,2,3,4,4a,10b-hexahydro -benzo(c)(1,6)naphthyridine.
 24. The compound of claim 1, which is cis-8,9-Dimethoxy-2-methyl-6-(2,3-dimethylphenyl)-1,2,3,4,4a, 10b-hexahydro-benzo(c)(1,6)naphthyridine.
 25. The compound of claim 1, which is cis-8,9-Dimethoxy-2-methyl-6-(3,5-dimethylphenyl)-1,2,3,4,4a, 10b-hexahydro-benzo(c)(1,6)naphthyridine.
 26. The compound of claim 1, which is cis-8,9-Dimethoxy-2-methyl-6-(2,4-dimethylphenyl)-1,2,3,4,4a, 10b-hexahydro-benzo(c)(1,6)naphthyridine.
 27. The compound of claim 1, which is cis-8,9-Dimethoxy-6-(2,3-dimethoxyphenyl)-2-methyl-1,2,3,4,4a, 10b-hexahydro-benzo(c)(1,6)naphthyridine.
 28. The compound of claim 1, which is cis-8,9-Dimethoxy-6-(3,5-dimethoxyphenyl)-2-methyl-1,2,3,4,4a, 10b-Hexahydro-benzo(c)(1,6)naphthyridine.
 29. The compound of claim 1, which is cis-8,9-Dimethoxy-2-methyl-6-(3-methyl-4-nitrophenyl)-1,2,3,4, 4a,10b-hexahydro-benzo(c)(1,6)naphthyridine.
 30. The compound of claim 1, which is cis-6-(4-Chloro-3-nitrophenyl)-8,9-dimethoxy-2-methyl-1,2,3,4, 4a,10b-hexahydro-benzo(c)(1,6)naphthyridine.
 31. The compound of claim 1, which is cis-8,9-Dimethoxy-2-methyl-6-(4-methyl-3-nitrophenyl)-1,2,3,4, 4a,10b-hexahydro-benzo(c)(1,6)naphthyridine.
 32. The compound of claim 1, which is cis-6-(3-Aminophenyl)-8,9-dimethoxy-2-methyl-1,2,3,4,4a,10b-hexahydro -benzo(c)(1,6)naphthyridine.
 33. The compound of claim 1, which is cis-6-(2-Aminophenyl)-8,9-dimethoxy-2-methyl-1,2,3,4,4a,10b-hexahydro -benzo(c)(1,6)naphthyridine.
 34. The compound of claim 1, which is cis-6-(3-Acetanilido)-8,9-dimethoxy-2-methyl-1,2,3,4,4a,10b-hexahydro -benzo(c)(1,6)naphthyridine.
 35. The compound of claim 1, which is cis-8,9-Dimethoxy-2-methyl-6-(4-propionylaminophenyl)-1,2,3,4, 4a,10b-hexahydro-benzo(c)(1,6)naphthyridine.
 36. The compound of claim 1, which is cis-8,9-Dimethoxy-2-methyl-6-(4-pivaloylaminophenyl)-1,2,3,4,4a, 10b-hexahydro-benzo(c)(1,6)naphthyridine.
 37. The compound of claim 1, which is cis-6-(4-Benzoylaminophenyl)-8,9-dimethoxy-2-methyl-1,2,3,4,4a, 10b-hexahydro-benzo(c)(1,6)naphthyridine.
 38. The compound of claim 1, which is cis-6-(3-Benzoylaminophenyl)-8,9-dimethoxy-2-methyl-1,2,3,4,4a, 10b-hexahydro-benzo(c)(1,6)naphthyridine.
 39. The compound of claim 1, which is cis-6-(4-Formamidophenyl)-8,9-dimethoxy-2-methyl-1,2,3,4,4a,10b-hexahydro -benzo(c)(1,6)naphthyridine.
 40. The compound of claim 1, which is cis-6-(3-Formamidophenyl)-8,9-dimethoxy-2-methyl-1,2,3,4,4a,10b-hexahydro -benzo(c)(1,6)naphthyridine.
 41. A compound of claim 1, wherein the radical A-CO- is selected from stearyl, phenacetyl, 2,4-dimethylphenacetyl, 3,5-dimethoxy-phenacetyl, 2-fluoro- or 2-chloro or 2-bromo-benzoyl, cinnamoyl, nicotinoyl, 3-thenoyl, 3-furoyl and 2-pyrroyl.
 42. A compound of claim 1, wherein R1 is hydrogen, alkyl of one to three carbon atoms, alkoxy of one to three carbon atoms or alkylthio of one to three carbon atoms, fluorine, bromine, chlorine, nitro, trifluoromethyl, amino or amido of two to four carbon atoms, R2 is hydrogen, chlorine, alkyl of one to three carbon atoms or alkoxy of one to three carbon atoms, and R3 and R4 are both hydrogen or methoxy, or R3 and R4 together are methylenedioxy, or a pharmaceutically acceptable acid addition salt thereof.
 43. A compound of claim 1 of the formula:
 44. A compound of claim 43, wherein R is hydrogen.
 45. A compound of claim 43, wherein R is alkyl of 1 to 17 carbon atoms.
 46. A compound of claim 43, wherein R is furyl, thienyl, pyrrolyl, or pyridyl.
 47. A compound of claim 43, wherein A is a bond, alkylene or vinylene.
 48. A compound of claim 43, wherein R is alkyl of one to three carbon atoms.
 49. A compound of claim 43, of the formula,
 50. A compound of claim 49, wherein R'' is hydrogen.
 51. The compound of claim 43, which is Cis-6-(4-caproylaminophenyl)-8,9-dimethoxy-2-methyl-1,2,3,4,4a, 10b-hexahydro-benzo(c)(1,6)naphthyridine.
 52. The compound of claim 43, which is Cis-6-(4-lauroylamidophenyl)-8,9-dimethoxy-2-methyl-1,2,3,4,4a, 1-hexahydro-benzo(c)(1,6)naphthyridine.
 53. The compound of claim 43, which is Cis-8,9-dimethoxy-2-methyl-6-(4-stearoylamidophenyl)-1,2,3,4,4a, 10b-hexahydro-benzo(c)(1,6)naphthyridine.
 54. The compound of claim 43, which is Cis-8,9-dimethoxy-2-methyl-6-(4-nonanoylaminophenyl)-1,2,3,4,4a, 10b-hexahydro-benzo(c)(1,6)naphthyridine.
 55. The compound of claim 43, which is Cis-8,9-dimethoxy-2-methyl-6-(4-pentanoylaminophenyl)-1,2,3,4, 4a,10b-hexahydro-benzo(c)(1,6)naphthyridine.
 56. The compound of claim 43, which is Cis-6-(4-isobutyroylaminophenyl)-8,9-dimethoxy-2-methyl-1,2,3,4, 4a10b-hexahydro-benzo(c)(1,6)naphthyridine.
 57. The compound of claim 43, which is Cis-6-(4-(2-furoylamino)phenyl)-8,9-dimethoxy-2-methyl-1,2,3,4, 4a,10b-hexahydro-benzo(c)(1,6)naphthyridine.
 58. The compound of claim 43, which is Cis-8,9-dimethoxy-2-methyl-4-(4-(2-thenoylamino)phenyl)-1,2,3,4, 4a,10b-hexahydro-benzo(c)(1,6)naphthyridine.
 59. The compound of claim 43, which is Cis-8,9-dimethoxy-2-methyl-6-(4-nicotinoylaminophenyl)-1,2,3,4, 4a,10b-hexahydro-benzo(c)(1,6)naphthyridine.
 60. The compound of claim 43, which is Cis-6-(4-(4-chlorobenzamido)phenyl)-8,9-dimethoxy-2-methyl-1,2, 3,4,4a,10b-hexahydro-benzo(c)(1,6)naphthyridine.
 61. The compound of claim 43, which is Cis-8,9-dimethoxy-2-methyl-6-(4-phenylacetamidophenyl)-1,2,3,4, 4a,10b-hexyhydro-benzo(c)(1,6)naphthyridine.
 62. The compound of claim 43, which is Cis-6-(4-cinnamoylaminophenyl)-8,9-dimethoxy-2-methyl-1,2,3,4, 4a,10b-hexahydro-benzo(c)(1,6)naphthyridine.
 63. The compound of claim 43, which is Cis-6-(4-(3-methyl-4-methoxybenzamido)phenyl)-8,9-dimethoxy-2-methyl -1,2,3,4,4a,10b-hexahydro-benzo(c)(1,6)naphthyridine.
 64. The compound of claim 43, which is Cis-6-(4(4-bromobenzamido)phenyl)-8,9-dimethoxy-2-methyl-1,2,3, 4,4a,10b-hexahydro-benzo(c)(1,6)naphthyridine.
 65. The compound of claim 43, which is Cis-6-(4-(4-fluorobenzamido)phenyl)-8,9-dimethoxy-2-methyl-1,2, 3,4,4a,10b-hexahydro-benzo(c)(1,6)naphthyridine.
 66. A compound of claim 1, wherein R1 is hydrogen, alkyl, alkoxy, alkylthio, fluorine, brOmine, chlorine, nitro or trifluoromethyl.
 67. A compound of claim 66, wherein R2 is hydrogen, chlorine or alkoxy.
 68. A compound of claim 1, wherein R1 is amino.
 69. A compound of claim 1, wherein R1 is acetamido.
 70. A compound of claim 1, wherein R2 is hydrogen. 